Shotgun choke



Sept. 30, 1947. J. J. LIMON 2,428,232

SHOTGUN CHOKE Filed May 25, 1944 Y INVENTOR. Jase viz iLz'nzan ATI'CI R N EYE Patented Sept. 30, l 947 UNITED STATES PATENT OFFICE SHOTGUN CHOKE Joseph J. Limon, Bayonne, N. J.

Application May 25, 1944, Serial No. 537,330 I 1 Claim. 1

This invention appertains to chokes for shot guns, and has for one of its several objects to provide a choke attachment for any standard make of single-barrel shotgun, which is adapted to be mounted on the barrel and may be adjusted.

Another object of the invention has to do with making the choke attachment in telescopic sections, in combination with a simple means to effect adjustment of the sections in a manner that the shot can be delivered in varying patterns, at the will of the user.

In the straight-barreled or non-choking gun only thirty per cent of the shot in the charge reach a target thirty inches in diameter at a distance of forty yards. With the choke-bore barrel, other things being equal, seventy per cent of the shot is delivered within the thirty inch circle. The generally accepted explanation of this result is that the choke momentarily holds back the wad, and with it the forcibly expandin gases which otherwise have a tendency to scatter the shot laterally just as they leave the muzzle. It is therefore the main purpose of the instant invention to provide the sportsman, or other user, with a choke that, will permit him to change the shot pattern between these extremes at will, as may be desirable or necessary from time to time.

According to my invention I provide a series of ports around the circumference of the choke to permit a limitedlateral expansion of the gases, and further the extensible cylindrical bore for the choke is fashioned to form an interior chamber which may be expanded in area by adjustment of the cylindrical bore. This bore is of lesser diameter than the bore of the shotgun barrel and the charge will be constricted passing therethrough while the" gases will expand laterally thus concentrating the charge forwardly rather than laterally as the expansion chamber is increased in area.

With the foregoing and other objects and advantages in view, the invention resides in the certain new and useful combination, construction, and arrangement of parts, as will be hereinafter more fully described, set forth in the appended claim, and illustrated in the accompanying drawing, in which:

Figure 1 is a side view of the muzzle end of a shotgun barrel, with the adjustable choke applied thereto, in accordance with the invention;

Figure 2 is a longitudinal section, taken through the line 2-2 of Figure 1;

Figure 3 is a side view of the barrel attaching section per se;

Figure 4 is a view similar to that of Figure 3, but showing the telescopically adjustable choke section; and,

Figure 5 is an end view of the mounting tube for attaching the choke to the end of a gun barrel on'an enlargedscale and with the parts exaggerated for the purpose of illustration,

Referring to the drawing, the embodiment of the invention, as it is exemplified therein, is generally comprised in a tubular body, formed of telescopic lengths of steel tubing, with means for attaching the outer tube II to the muzzle end of a shotgun barrel Ill and other means for adjusting the inner tube l'l relatively thereto.

As shown, the outer tube .H has the inner end of its bore screw threaded, as at l2, for engagement with the complementally screw threaded muzzle end of the gun barrel l0. Forwardly of the terminus of the screw thread I 2, the outer tube H is provided with a series of circumferentially spaced exhaust ports 13 and these function to prevent distortion of the firing pattern. The ports or openings [3 relieve the pressure at this point, but by sacrificing this pressure energy it.

is possible to obtain higher chamber pressure and therefore, higher velocity, and thereby produce a better pattern. The forward end of the tube I l is exteriorly screwthreaded and longitudinally split, as at l4, to provide anumber of segments l5, which have inwardly-extending beads H5 at the ends as shown in Figure 2. Also the bore 5 of the tube length II is enlarged from a shoulder 6 adjacent the exhaust ports l3 to the forward end, so that this portion of its length is less rigid than the inner end portion thereof.

Telescopically engaged in the forward end of the tube I I, is the second or inner tube I 1, which has an exterior diameter adapting it for snug sliding fit in the enlarged bore 5 of the tube l I, and its bore 1 is of a diameter substantially less than that of the bore 8 of the inner end portion of the tube II, the diameter of the latter bore 8 being equal to that of the gun barrel E0. The inner end of the bore 1 of the tube I1 is flared, as at l8, to a substantially feathered edge, which abuts the shoulder 6 connecting the diiferent bore sections of the outer tube H, and the tube length I 1 when the tube i1 is disposed at its innermost position and forms a variable chamber 9 between the shoulder 6 and the reduced bore 7. Equidistantly spaced along an intermediate length of the tube [1, is a series of circumferentially extending grooves l9, which indicates different positions of its adjustment relatively to the outer tube H. The extreme outer end of the 3 tube I1 is knurled, as at 20, to facilitate its manipulation relatively to the tube ll.

Engaged about the forward end portion of the tube l1, and with the screw thread .on the forward end of the tube I I, is a clamp nut 2| which, when tightened up on the segments l5, forces the beads 16 at the ends of the segments into engagement with one of the annular grooves l9, of the tube 11, thus securing the latter tube inany one of its selective positions of adjustment relatively to the tube H.

In use, and with the outer tube ll attached to the muzzle of the gun barrel ID, the clamp nut N is loosened on the segments IE to permit the,

free ends with the beads iii of the latter to move outwardly from their engagement with the annular groove I9 occupied by the, same at the moment, when the inner tube 11 is manually adjusted relatively to the outer tube l I, to any one of its choke forming positions, as indicated by the. annular grooves 119. registering 'With the beads. [6i of the segments 1-5. "*W-hn'adjust'ed. as desired, tightening up on the clamp nut '2! forces the. segment beads. L16; intofengagement with the particular groove [9; registering. therewith, so that thev inner. tube. I].- is rigidly. secured. tothe outer tube, H. Ero'm this, it will be. obvious that the inner tube. l 'liconstitutes a firing. pattern. controland that each. of the annular grooves l9. represents afd-ifierent choke' formation. The choke. tube l1, being positionedl'at the. extreme end of. the. gun barrel forms the. muzzle. thereof and therefore',' influencesthe pattern, and in combination with the exhaust openings a' slight adjustment lengthwise obviously governs the amount. of relief ofpressure on the charge prior toits leaving the choketube;therebywarying the pattern. r

' Having. thus fully describedmy.invention, it is to be. unde'rstoodfthat minor changes in the design and. construction of thepart's 'of. the variable choke attachment forming .the.subjectmatte'ri' thereof. may, be resorted to; without departing from. the spirit of the invention. or its scope asclaimed. M

What, I claim is:

In a chokeattachment forthemuzzles of gunbarrels, the combination, which comprises, a mounting tubehaving internal. threadsinflone endfor connecting the attachment to .the muzzle of :al gun. barrel and threads on-the outer. surf ace of the opposite end, said tube having spaced radially positioned exhaust openings therethrough spaced from the inner end of the internal threads providing escape of a limited amount of charge .propellent gases therethrough for relieving the pressure energy at this point, an internal shoulder spaced from said exhaust openings with the bore of the tube from the shoulder to the end thereof slightly larger than the bore of the section thereof from the shoulder to theinner end of the-internal threads, and spaced longitudinally disposed kerfs extending inward from the outer end through the said threads on the outer surface thereof providing spring sections with beads on the inner surfaces of the ends thereof, an inner choke tube longitudinally slidable in the said-mounting tube, said choke tube having an internally beveled inner end and spaced adjusting circumferential grooves in the peripheral surface, and a clamp nut threaded on the threaded outer. end of. the mounting tubehaving a converging inner. surface positioned to coast with. the. outer ends of the. said: springsections. of the mounting. tube to wedge. the beads. on the, inner. surfaces thereof: into the said; circumferential grooves of the choke tube, whereby the choke, tube. may be locked. in desired longitudinal adjusted positions. thereby governing the. amount of. relief of pressure on the. charge prior. to its leaving the device andaccordingly. varying the pattern.

JOSEPH: J1 LIMON.

REFEREN IT D The following references are of record in the fileof this patent:

UNITED STATES PATENTS.

Switzerland.-. Mar, 16, 1928. 

